1. Field of Invention
This invention relates generally to fluid control systems. Particularly, this invention relates to a modular mounting system for chemical fluid control components of a chemical fluid control system.
2. Description of Prior Art
Fluid control components are used to control the delivery of a fluid (i.e., a gas or liquid) in industrial processes. Chemical delivery systems are used in numerous industries to control the flow of fluids, including gas reactants and other chemicals (e.g., liquids). Fluid control components are used to condition and control the delivery of fluids. Usually, these components are arranged so that fluid is carried through each of the components. For example, in semiconductor processing equipment, a variety of fluid control components are configured in a gas stick, which precisely controls the delivery of various fluids during semiconductor processing. In semiconductor processing, these systems are commonly used to control the flow of gases to and from processing chambers. Such processing often makes demanding requirements of chemical delivery systems. In chemical etch processes, for example, gas lines usually must be periodically changed out because of line corrosion and/or partial or complete system reconfiguration during maintenance. To minimize the downtime of the etch tool to which a chemical delivery system is attached, the gas lines of the chemical delivery system should be capable of quick removal and replacement.
FIG.1 illustrates a prior art gas stick (20). The gas stick (20) includes a set of fluid control components joined by multiple welds and fittings. One fluid control component depicted in FIG.1 is a shut-off valve (22). A pipe section (26) links the shut-off valve (22) to a sleeve or fitting (28) associated with a manual pressure regulator (24). The manual pressure regulator (24) has a fitting (30) on its opposite side for connection with a pipe section (32). Pipe section (32) is connected to a fitting (36) associated with a pressure transducer (34). The opposite side of the pressure transducer (34) also has a fitting (38) for connection with another pipe section. The remaining components in the figure are similarly configured with fittings for attachments to pipe sections. The gas stick (20) is attached to a substrate. Other gas sticks (not shown) may also be attached to the substrate to form a gas panel.
Those skilled in the art recognize a number of problems associated with prior art gas sticks of the type illustrated in FIG. 1. First, the multiple fittings and pipe sections need to be welded or otherwise secured to one another. The assembly of these components can be relatively labor intensive. Similarly, the disassembly of these components for repair or replacement can be extremely labor-intensive.
Another problem associated with gas stick (20) is that the numerous fittings and pipe sections produce a relatively long and heavy device. The attachment of the gas stick (20) to a substrate (50) also produces problems since the entire gas stick (20) must be removed from the substrate (50) in order to repair the gas stick (20).
Efforts to alleviate these problems have resulted in the use of interconnecting blocks on which components are mounted. These blocks contain machined passages through which gas flows, being directed in and out of components.
Interconnections between blocks or between sticks invariably include seals from block to block which result in additional complexity and accompanying degradation of system reliability. Additionally, sealing integrity is compromised in some cases by placing two or more seals between blocks to be compressed in series. The problem being that the degree of compression of the seals cannot be guaranteed to be equal at each junction; since a single joining force is applied to all seals in series and simultaneously. FIG. 2 shows prior art that makes use of rectangular blocks to build a gas panel composed of multiple gas sticks. Components such as valves, pressure regulators and mass flow controllers are mounted above the blocks by use of suitable fasteners and seals. Seals are used to make hermetic connections between blocks. All seals corresponding to a column of blocks are compressed using long fasteners that traverse all blocks.
Additionally, interconnection between sticks is accomplished using a second plane of transversal series of blocks. Seals are used to interconnect between the two planes of blocks.
Other prior art eliminates the use of two planes of blocks by incorporating into blocks gas passages for flow along the orientation of sticks and gas passages for flow between sticks. FIG. 3 illustrates this approach. However, seals are still required between blocks within a stick and between sticks.
Furthermore, it is common for entire gas sticks to become contaminated or corroded necessitating their replacement, as is the case, for example, in semiconductor fabrication processes that use SiH4 in its gaseous state. Modular configurations, which include seals between sticks, preclude replacement of an entire stick without removal of neighboring sticks. It would be highly desirable to improve access such that replacing either any component or stick would not affect neighboring components or sticks.
What is needed is a gas stick that allows for the quick removal and replacement of system components. What is also needed is a gas stick that requires a minimum of labor-intensive welds and connections between components. Additionally, what is needed is a gas stick that does not require seals and gaskets to connect component blocks. Also, a lightweight and easy to assemble gas stick is needed.